getting ags point from opengl

[HamzaHaroon]

I need to get the ags point on the map (point with long and lat) on a opengl view. right now i have it to getting the user touch on the screen, which is x and y. how can this be done if my glview controlling class is seperate from the mapview controller?

this is how i get input

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { CGRect bounds = [self bounds];     UITouch*    touch = [[event touchesForView:self] anyObject]; firstTouch = YES; // Convert touch point from UIView referential to OpenGL one (upside- down flip) location = [touch locationInView:self]; location.y = bounds.size.height - location.y; } // Handles the continuation of a touch. - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {        CGRect bounds = [self bounds]; UITouch* touch = [[event touchesForView:self] anyObject];      // Convert touch point from UIView referential to OpenGL one (upside- down flip) if (firstTouch) { firstTouch = NO; previousLocation = [touch previousLocationInView:self]; previousLocation.y = bounds.size.height - previousLocation.y; } else { location = [touch locationInView:self];     location.y = bounds.size.height - location.y; previousLocation = [touch previousLocationInView:self]; previousLocation.y = bounds.size.height - previousLocation.y; }      // Render the stroke [self renderLineFromPoint:previousLocation toPoint:location]; } // Handles the end of a touch event when the touch is a tap. - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { CGRect bounds = [self bounds];     UITouch*    touch = [[event touchesForView:self] anyObject]; if (firstTouch) { firstTouch = NO; previousLocation = [touch previousLocationInView:self]; previousLocation.y = bounds.size.height - previousLocation.y; [self renderLineFromPoint:previousLocation toPoint:location]; } }

here is the code i have for drawing based on user touch

// Drawings a line onscreen based on where the user touches - (void) renderLineFromPoint:(CGPoint)start toPoint:(CGPoint)end { static GLfloat*     vertexBuffer = NULL; static NSUInteger   vertexMax = 64; NSUInteger vertexCount = 0,     count,     i; [EAGLContext setCurrentContext:context]; glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer); // Convert locations from Points to Pixels CGFloat scale = self.contentScaleFactor; start.x *= scale;PaintingView.m 12-08-07 9:34 AM start.y *= scale; end.x *= scale; end.y *= scale; // Allocate vertex array buffer if(vertexBuffer == NULL) vertexBuffer = malloc(vertexMax * 2 * sizeof(GLfloat)); // Add points to the buffer so there are drawing points every X pixels count = MAX(ceilf(sqrtf((end.x - start.x) * (end.x - start.x) + (end.y -  start.y) * (end.y - start.y)) / kBrushPixelStep), 1); for(i = 0; i < count; ++i) { if(vertexCount == vertexMax) { vertexMax = 2 * vertexMax; vertexBuffer = realloc(vertexBuffer, vertexMax * 2 * sizeof (GLfloat)); } vertexBuffer[2 * vertexCount + 0] = start.x + (end.x - start.x) *  ((GLfloat)i / (GLfloat)count); vertexBuffer[2 * vertexCount + 1] = start.y + (end.y - start.y) *  ((GLfloat)i / (GLfloat)count); vertexCount += 1; } // Render the vertex array glVertexPointer(2, GL_FLOAT, 0, vertexBuffer); glDrawArrays(GL_POINTS, 0, vertexCount); // Display the buffer glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer); [context presentRenderbuffer:GL_RENDERBUFFER_OES]; }

[NimeshJarecha]

You can create AGSMutablePolyline or AGSMutablePolygon (based on geometry you want to draw) and keep adding AGSPoint converted from each touch (UITouch). Here is the code of conversion.

- (AGSPoint*)getMapPointFromTouchs:(NSSet *)touches {
    UITouch *mytouch=[[touches allObjects] objectAtIndex:0];
    CGPoint touchPoint = [mytouch locationInView:self];
    AGSPoint *mapPoint = [self.mapView toMapPoint:touchPoint];
    return mapPoint;
}

Regards,
Nimesh

[HamzaHaroon]

i added that method, but I'm not getting any coordinates. i think its because i didn't set the mapView properly. here is my code for this class, and its header file. I'm new to arcgis and iOS, so i don't know how to properly set the mapView spatial reference to get the points based on touch.

#import <UIKit/UIKit.h>
#import <OpenGLES/EAGL.h>
#import <OpenGLES/ES1/gl.h>
#import <OpenGLES/ES1/glext.h>
#import <ArcGIS/ArcGIS.h>

//CONSTANTS:

#define kBrushOpacity  (1.0 / 3.0)
#define kBrushPixelStep  1
#define kBrushScale   1
#define kLuminosity   0.75
#define kSaturation   1.0

//CLASS INTERFACES:

@interface PaintingView : UIView
{
    AGSMapView* _mapView;
 AGSGraphicsLayer* _graphicsLayer;
@private
 // The pixel dimensions of the backbuffer
 GLint backingWidth;
 GLint backingHeight;
 
 EAGLContext *context;
 
 // OpenGL names for the renderbuffer and framebuffers used to render to this view
 GLuint viewRenderbuffer, viewFramebuffer;
 
 // OpenGL name for the depth buffer that is attached to viewFramebuffer, if it exists (0 if it does not exist)
 GLuint depthRenderbuffer;
 
 GLuint brushTexture;
 CGPoint location;
 CGPoint previousLocation;
    
    AGSPoint *currentPoint;
    AGSPoint *previousPoint;
 
    Boolean firstTouch;
 Boolean needsErase;
 AGSMutableMultipoint *lines;
}

@property(nonatomic, readwrite) CGPoint location;
@property(nonatomic, readwrite) CGPoint previousLocation;
@property(nonatomic, readwrite) AGSMutableMultipoint *lines;
//@property(nonatomic, retain) AGSMapView mapView;

- (void)erase;
- (void)setBrushColorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue;
- (void)update;

@end

[HamzaHaroon]

//  PaintingView.m

#import <QuartzCore/QuartzCore.h>
#import <OpenGLES/EAGLDrawable.h>
#import "PaintingView.h"

//CLASS IMPLEMENTATIONS:

// A class extension to declare private methods
@interface PaintingView (private)

- (BOOL)createFramebuffer;
- (void)destroyFramebuffer;

@end

@implementation PaintingView

@synthesize  location;
@synthesize  previousLocation;
@synthesize  lines;

+ (Class) layerClass
{
 return [CAEAGLLayer class];
}

// The GL view is stored in the nib file. When it's unarchived it's sent -initWithCoder:
- (id)initWithCoder:(NSCoder*)coder mapView:(AGSMapView*) mapView graphicsLayer:(AGSGraphicsLayer*)graphicsLayer {
 
    _mapView = mapView;
    _graphicsLayer = graphicsLayer;
    lines = [[AGSMutableMultipoint alloc] initWithSpatialReference:_mapView];
    
 NSMutableArray* recordedPaths;
 CGImageRef  brushImage;
 CGContextRef brushContext;
 GLubyte   *brushData;
 size_t   width, height;
    
    if ((self = [super initWithCoder:coder])) {
  CAEAGLLayer *eaglLayer = (CAEAGLLayer *)self.layer;
  
  eaglLayer.opaque = YES;
  // In this application, we want to retain the EAGLDrawable contents after a call to presentRenderbuffer.
 
        eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
          [NSNumber numberWithBool:YES], kEAGLDrawablePropertyRetainedBacking, kEAGLColorFormatRGBA8, kEAGLDrawablePropertyColorFormat, nil];
  
  context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];
  
  if (!context || ![EAGLContext setCurrentContext:context]) {
   [self release];
   return nil;
  }
  
  // Create a texture from an image
  // First create a UIImage object from the data in a image file, and then extract the Core Graphics image
  brushImage = [UIImage imageNamed:@"Particle1.png"].CGImage;
  
  // Get the width and height of the image

  width = 5;
  height= 10;
  
  // Make sure the image exists
  if(brushImage) {
   // Allocate  memory needed for the bitmap context
   brushData = (GLubyte *) calloc(width * height * 4, sizeof(GLubyte));
   // Use  the bitmatp creation function provided by the Core Graphics framework. 
   brushContext = CGBitmapContextCreate(brushData, width, height, 15, width * 8, CGImageGetColorSpace(brushImage), kCGImageAlphaPremultipliedLast);
   // After you create the context, you can draw the  image to the context.
   CGContextDrawImage(brushContext, CGRectMake(0.0, 0.0, (CGFloat)width, (CGFloat)height), brushImage);
   // You don't need the context at this point, so you need to release it to avoid memory leaks.
   CGContextRelease(brushContext);
   // Use OpenGL ES to generate a name for the texture.
   glGenTextures(1, &brushTexture);
   // Bind the texture name. 
   glBindTexture(GL_TEXTURE_2D, brushTexture);
   // Set the texture parameters to use a minifying filter and a linear filer (weighted average)
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   // Specify a 2D texture image, providing the a pointer to the image data in memory
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, brushData);
   // Release  the image data; it's no longer needed
            free(brushData);
  }
  
  // Set the view's scale factor
  self.contentScaleFactor = 1.0;
        
  // Setup OpenGL states
  glMatrixMode(GL_PROJECTION);
  CGRect frame = self.bounds;
  CGFloat scale = self.contentScaleFactor;
  // Setup the view port in Pixels
  glOrthof(0, frame.size.width * scale, 0, frame.size.height * scale, -1, 1);
  glViewport(0, 0, frame.size.width * scale, frame.size.height * scale);
  glMatrixMode(GL_MODELVIEW);
  glDisable(GL_DITHER);
  glEnable(GL_TEXTURE_2D);
  glEnableClientState(GL_VERTEX_ARRAY);
     glEnable(GL_BLEND);
  // Set a blending function appropriate for premultiplied alpha pixel data
  glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
  glEnable(GL_POINT_SPRITE_OES);
  glTexEnvf(GL_POINT_SPRITE_OES, GL_COORD_REPLACE_OES, GL_TRUE);
  glPointSize(width / kBrushScale);
  glColor4f(0.5f,0.1f,1.0f,1.0f);  
        // Make sure to start with a cleared buffer
  needsErase = YES;
  
  // Playback recorded path, which is "Shake Me"
  recordedPaths = [NSMutableArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"Recording" ofType:@"data"]];
  if([recordedPaths count])
   [self performSelector:@selector(playback:) withObject:recordedPaths afterDelay:0.2];
 }
 [self setBackgroundColor:[UIColor clearColor]];
    
    //self.userInteractionEnabled = NO;
    
    return self;
    
}

-(void)layoutSubviews
{
 [EAGLContext setCurrentContext:context];
 [self destroyFramebuffer];
 [self createFramebuffer];
 
 // Clear the framebuffer the first time it is allocated
 if (needsErase) {
  [self erase];
  needsErase = NO;
 }
}

- (BOOL)createFramebuffer
{
 // Generate IDs for a framebuffer object and a color renderbuffer
 glGenFramebuffersOES(1, &viewFramebuffer);
 glGenRenderbuffersOES(1, &viewRenderbuffer);
 
 glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
 glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
 [context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(id<EAGLDrawable>)self.layer];
 glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer);
 
 glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
 glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);
 
 glGenRenderbuffersOES(1, &depthRenderbuffer);
 glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);
 glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, backingWidth, backingHeight);
 glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);
 
 if(glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES)
 {
  NSLog(@"failed to make complete framebuffer object %x", glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES));
  return NO;
 }
 return YES;
}

// Clean up any buffers we have allocated.
- (void)destroyFramebuffer
{
 glDeleteFramebuffersOES(1, &viewFramebuffer);
 viewFramebuffer = 0;
 glDeleteRenderbuffersOES(1, &viewRenderbuffer);
 viewRenderbuffer = 0;
 
 if(depthRenderbuffer)
 {
  glDeleteRenderbuffersOES(1, &depthRenderbuffer);
  depthRenderbuffer = 0;
 }
}

// Releases resources when they are not longer needed.
- (void) dealloc
{
 if (brushTexture)
 {
  glDeleteTextures(1, &brushTexture);
  brushTexture = 0;
 }
 
 if([EAGLContext currentContext] == context)
 {
  [EAGLContext setCurrentContext:nil];
 }
 
 [context release];
 [super dealloc];
}


// Erases the screen
- (void) erase
{
 [EAGLContext setCurrentContext:context];
 
 // Clear the buffer
 glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
 glClearColor(0.0, 0.0, 0.0, 0.0);
 glClear(GL_COLOR_BUFFER_BIT);
 
 // Display the buffer
 glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
 [context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

[HamzaHaroon]

// Drawings a line onscreen based on where the user touches
- (void) renderLineFromPoint:(AGSPoint*)astart toPoint:(AGSPoint*)aend//(CGPoint)start toPoint:(CGPoint)end
{
 static GLfloat*  vertexBuffer = NULL;
 static NSUInteger vertexMax = 64;
 NSUInteger   vertexCount = 0, count, i;
 CGPoint start = [_mapView toScreenPoint:astart];
        CGPoint end = [_mapView toScreenPoint:aend];
   
 [EAGLContext setCurrentContext:context];
 glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
 
 // Convert locations from Points to Pixels
 CGFloat scale = self.contentScaleFactor;
 start.x *= scale;
 start.y *= scale;
 end.x *= scale;
 end.y *= scale;
 
 // Allocate vertex array buffer
 if(vertexBuffer == NULL)
  vertexBuffer = malloc(vertexMax * 2 * sizeof(GLfloat));
 
 // Add points to the buffer so there are drawing points every X pixels
 count = MAX(ceilf(sqrtf((end.x - start.x) * (end.x - start.x) + (end.y - start.y) * (end.y - start.y)) / kBrushPixelStep), 1);
 for(i = 0; i < count; ++i) {
  if(vertexCount == vertexMax) {
   vertexMax = 2 * vertexMax;
   vertexBuffer = realloc(vertexBuffer, vertexMax * 2 * sizeof(GLfloat));
  }
  
  vertexBuffer[2 * vertexCount + 0] = start.x + (end.x - start.x) * ((GLfloat)i / (GLfloat)count);
  vertexBuffer[2 * vertexCount + 1] = start.y + (end.y - start.y) * ((GLfloat)i / (GLfloat)count);
  vertexCount += 1;
 }
 
 // Render the vertex array
 glVertexPointer(2, GL_FLOAT, 0, vertexBuffer);
 glDrawArrays(GL_POINTS, 0, vertexCount);
 
 // Display the buffer
 glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
 [context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

//Returns a map point based on user touch on screen.

-(AGSPoint*)getMapPointFromTouch:(NSSet *)touches
{
    UITouch *myTouch = [[touches allObjects] objectAtIndex:0];
    CGPoint touchPoint = [myTouch locationInView:self];
    AGSPoint *mapPoint = [_mapView toMapPoint:touchPoint];
    return mapPoint;
}

// Reads previously recorded points and draws them onscreen. This is the Shake Me message that appears when the application launches.
- (void) playback:(NSMutableArray*)recordedPaths
{
 NSData*    data = [recordedPaths objectAtIndex:0];
 AGSPoint*   point = (AGSPoint*)[data bytes];
 NSUInteger   count = [data length] / sizeof(CGPoint),
    i;
 
 // Render the current path
 for(i = 0; i < count - 1; ++i)//, ++point)
  [self renderLineFromPoint:[lines pointAtIndex:i] toPoint:[lines pointAtIndex:i+1]];
        //[self renderLineFromPoint:*point toPoint:*(point + 1)];
 
 // Render the next path after a short delay 
 [recordedPaths removeObjectAtIndex:0];
 if([recordedPaths count])
  [self performSelector:@selector(playback:) withObject:recordedPaths afterDelay:0.0];
}

// Handles the start of a touch
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    AGSPoint* coord = [[event touchesForView:_mapView] anyObject];
 CGRect  bounds = [self bounds];
    UITouch* touch = [[event touchesForView:self] anyObject];
 firstTouch = YES;
 
    // get touch point and store are current point
    currentPoint = [self getMapPointFromTouch:touches];
    [lines addPoint: currentPoint];
}

// Handles the continuation of a touch.
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{  
    AGSPoint* coord = [[event touchesForView:_mapView] anyObject];
 CGRect    bounds = [self bounds];
 UITouch*   touch = [[event touchesForView:self] anyObject];
    
 // Convert touch point from UIView referential to OpenGL one (upside-down flip)
 if (firstTouch) {
  firstTouch = NO;
        
        previousPoint = [currentPoint copy];

 } else {
        previousPoint = [currentPoint copy];
        currentPoint = [self getMapPointFromTouch:touches];
        [lines addPoint:currentPoint];
 }
    
 // Render the stroke
    [self renderLineFromPoint:previousPoint toPoint:currentPoint];
}

// Handles the end of a touch event when the touch is a tap.
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
 CGRect   bounds = [self bounds];
        UITouch*   touch = [[event touchesForView:self] anyObject];
 if (firstTouch) {
  firstTouch = NO;
        previousPoint = [currentPoint copy];
        
        [self renderLineFromPoint:previousPoint toPoint:currentPoint];
 }
}

// Handles the end of a touch event.
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
}

- (void)setBrushColorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue
{
 // Set the brush color using premultiplied alpha values
 glColor4f(100.0f,50.0f,200.0f,1.0f);
}

@end

[NimeshJarecha]

Yes, map view must be properly initialized. Are you showing open gl view on top of map view? If yes, you should create a custom initializer for the open gl view and pass already initialized mapView to it.

Regards,
Nimesh

[HamzaHaroon]

yes, my opengl view comes up ontop of my mapView. I thougt i was initialzing my mapview in my initWithCoder: method. how should i be initializing it?

[NimeshJarecha]

Are you initializing open gl view with initWithCoder: method? If yes, you should create a custom init method as initWithCoder:mapView and pass already initialized mapView object from map view controller.

Regards,
Nimesh

[HamzaHaroon]

my painting classes are seperate from the view controller. i thought that this method should initialize my mapView
- (id)initWithCoder:(NSCoder*)coder mapView:(AGSMapView*) mapView graphicsLayer:(AGSGraphicsLayer*)graphicsLayer {

[NimeshJarecha]

That'll just pass the object. If it is initialized then it'll work otherwise not. You should pass already initialized mapView object to that method.

Regards,
Nimesh